Inflammatory bowel diseases Flashcards
1
Q
Ulcerative colitis (UC) vs Crohn’s disease (CD)
A
- Both are chronic inflammatory states of the gut
- CD can involve the entire length of the GI tract, but UC only affects the colon (starting w/ distal parts)
- UC shows rectum/sigmoid involvement almost always, is diffuse and doesn’t skip parts of the colon as it progresses more proximally
- CD usually involved both colon and ileum, but can involve any part go GI tract
- It is more segmented w/ some skipped areas and quite often leads to peri-anal lesions (abscess/fistulas)
- Recurrence more common
2
Q
IBD etiologies
A
- IBDs are chronic inflammatory conditions of GI tract characterized w/ relapsing course
- 4 main factors: genetic predisposition (NOD2 mutations), environmental factors, dysregulated immune system, and microbiome
- Part of the pathogenesis is due to the dysregulated immune system targeting the microbiome
- Some individuals are more susceptible to this (due to genes), leading them to produce cytokines (TNFa, IFNg, IL12) in response to commensal flora and thus increasing GI inflammation (Th1 mediated)
- There may also be defective innate immunity: loss of mucosal barrier
- Persistent infection w/ pathogens (mycobacterium, GN species) can potentially contribute to development of IBD
3
Q
IBD subtypes
A
- UC: colon only, inflammation is limited to mucosa, does not extend past muscularis mucosa
- There is continuous inflammation, starting at rectum and moving proximally
- CD: can be mouth-anus, most commonly in terminal ileum and colon (but can be confined to one or the other)
- Inflammation can be transmural, leads to cobblestoning and deep ulcers, strictures, perforations, fistulas
- The inflammation may be patchy, skipping areas, and often there is rectal sparing but peri-anal involvement (fistulas, abscesses, tags, fissures)
4
Q
Sxs for IBDs
A
- CD: ab pain, diarrhea (+/- blood), weight loss, perianal involvement, FTF, mouth ulcers
- UC: bloody mucous diarrhea (always + blood), ab pain, weight loss, tenesmus (urge to poop but colon is empty)
- P-ANCA is specific, but not sensitive, for UC (can help rule in, but a negative does not rule out)
- Signs common to both: low-grade fever, ab exam usually benign (if positive for guarding probably means complication), both can have extra-intestinal manifestations
5
Q
Extraintestinal manifestations
A
- MSK (most common): arthritis (T1 and T2), sacroilitis, ankylosing spondylitis
- Derm: erythema nodosum, pyoderma gangrenosum
- Ocular: uveitis, scerlitis, episcleritis
- Heme: anemia, hypercoagulability
- Misc: primary sclerosing cholangitis (usually UC), cholelithiasis (CD), nephrolitiasis (CD)
- Sxs that parallel IBD course: peripheral arthritis T1, sacroilitis, E nodosum, scleritis and episcleritis
6
Q
Appearance on endoscopy
A
- UC: rectal involvement in continuous patter
- CD: rectal sparing, patchy colitis, cobblestoning, linear/deep ulcers, ileal ulcers
7
Q
Complications
A
- Both: hemorrhage, perforation, CRC, anemia, stricture (more common in CD)
- UC only: toxic megacolon
- CD only: bowel obstruction, fistulas, abscesses, granulomas, creeping fat, absorption derangements (+ absorption of oxalate, - absorption of B12, bile acids)
- Toxic megacolon (emergency): extreme dilation of colon accompanied by fever, leukocytosis, tachycardia, anemia, dehydration/electrolyte imbalance, hypotension, AMS
8
Q
Pathology of UC
A
- Acute phase: diffuse hyperemia, superficial ulcers
- Chronic phase: flattened, atrophic mucosa, no thickening of wall and inflammation does not extend past mucosa
- May see inflammatory pseudopolyps (regenerating mucosa)
- Micro of acute phase: crypt distortion + cryptitis, crypt abscess (PMNs in crypts), superficial ulceration
- Micro of chronic phase: crypt atrophy (decreased in #) w/ branching, chronic inflammation of crypts/lamina propria
- CRC risk: increases w/ longer duration/extent (highest in pancolitis)
9
Q
Pathology of CD
A
- Acute phase: hyperemia + ulceration
- Mesenteric fat wraps around bowel wall (creeping fat)
- Cobblestone appearance (ulcers separated by normal mucosa)
- Chronic phase: thickened segmented “lead pipe” appearance
- Narrowed lumen +/- strictures (strictures more likely in SI than colon)
- Micro: transmural inflammation w/ lymphoid aggregates, cryptitis, crypt abscess
- Epithelioid grandmas seen in 50% of cases, may be in regional LNs
- Fissure ulcers, fistulas often seen
- CRC risk
10
Q
Differences in Rx protocols btwn UC and CD
A
- UC start mild (mesalamine), then increase intensity of Rx
- CD start w/ early aggressive Rx (steroid: budesonide) to prevent complications
11
Q
Mild Rxs
A
- 5 ASA (5 aminosalicylates): mesalamine
- First Rx option for UC, can lead to and maintain remission
- Inhibition of COX/LOX leads to decreased production of PGs and LTs
- This disrupts transcription of inflammatory mediators that are important in proliferative effects of TNFa
- Sometimes give antibios as adjunctive Rx for UC
- Sometimes give budesonide (oral, locally active steroid): fewer side effects b/c most is metabolized during first pass thru liver (used as 1st line Rx for CD)
- Budesonide only achieves remission, but cannot be used for maintenance
12
Q
Steroid Rx
A
- Used as a 2nd line of Rx for UC, but 3rd line of Rx for CD
- Most pts respond to 1st dose of steroids, but only 1/3rd remain in remission (1/3rd become steroid dependent)
- Predinsone is mostly used (has no benefit for maintenance, only induction of remission)
- Has many side effects: increases infection risk, osteoporosis, weight gain, glaucoma/cataract, edema, HTN, diabetes, adrenal suppression, muscle weakness, insomnia, moon facies, mood disturbances
13
Q
Immunomodulators
A
- 2nd line Rx for UC and CD
- Azathioprine -> 6-mercaptopurine (6MP)
- Both are purine analogs that inhibit DNA synthesis and reduce proliferation of B and T cells
- Side effects: leukopenia/infection, pancreatitis, lymphoma, GI intolerance, myalgia/fatigue, liver toxicity
14
Q
Biologics
A
- 3rd line Rx for UC, 2nd line Rx for CD
- Monoclonal Abs against mediators of inflammatory cascade (TNFa: Infliximab, adalumimab)
- Side effects: fever, chills, infection (reactivation of latent infections common: HBV AND TB), CHF exacerbation, increased risk for malignancies, liver failure in carriers of hep B
- MUST screen these pts for hep B and TB reactivation
15
Q
How to Rx CD/UC
A
- UC: 1st line is mesalamine (+/- budesonide and antibios)
- 2nd line is IV prednisone and/or 6MP/AZA
- 3rd line is biologics and/or surgery
- CD: 1st line is budesonide
- 2nd line is biologics and/or 6MP/AZA
- 3rd line is IV prednisone and/or surgery
- Mesalamine NOT used in CD
- Who to start combination Rx on: young age, deep ulcerations, fistulas, steroid resistance, severe disease, high risk anatomy
